//https://leetcode.cn/problems/best-time-to-buy-and-sell-stock-iv/

class Solution {
public:
    const int INF = 0x3f3f3f;
    int maxProfit(int k, vector<int>& prices) {
        int n = prices.size();

        vector<vector<int>> f(n, vector<int>(k + 1, -INF));
        auto g = f;

        f[0][0] = -prices[0], g[0][0] = 0;

        for (int i = 1; i < n; i++)
        {
            for (int j = 0; j <= k; j++)
            {
                f[i][j] = max(f[i - 1][j], g[i - 1][j] - prices[i]);
                g[i][j] = g[i - 1][j];
                if (j >= 1)
                    g[i][j] = max(g[i - 1][j], f[i - 1][j - 1] + prices[i]);
            }
        }

        int ret = 0;
        for (int i = 0; i <= k; i++)
        {
            ret = max(ret, g[n - 1][i]);
        }

        return ret;

    }
};